Researchers in Singapore recently determined that OCT assessment of the macular ganglion cell layer is comparable with the frequently used circumpapillary retinal nerve fiber layer (cpRNFL) thickness for the discrimination of early and moderate glaucoma, whereas cpRNFL thickness remains the most efficient parameter for advanced glaucoma. 

They also found that using the information from both macular and cpRNFL parameters may improve the detection of early glaucoma.

The study compared glaucoma patients and controls, 423 in each group. The researchers divided glaucoma eyes based on their visual field severity: early (n=234), moderate (n=107) and advanced (n=82). They obtained thickness measurements of each layer/sector and their corresponding areas under the receiver operating characteristic curves (AUC).

The two best parameters for detecting normal eyes from early glaucoma were cpRNFL and macular ganglion cell layer. For detecting moderate glaucoma, the best were macular ganglion cell layer combined with inner plexiform layer (IPL) and cpRNFL. The best combined parameters for detecting advanced glaucoma were macular ganglion cell layer with IPL and cpRNFL.

The study found that combining the two parameters improved diagnostic performance for early and moderate glaucoma but not for advanced disease.

The researchers suggest clinicians should use both macular and optic nerve head scans for the diagnosis of early glaucoma.

“Considering the application of individual retinal layers at the macula in glaucoma, an understanding on their distribution in different glaucoma severities may shed light on the mechanistic nature of glaucomatous structural damage,” they noted in their study.

Chua J, Tan B, Ke M, et al. Diagnostic ability of individual macular layers by spectral-domain optical coherence tomography in different stages of glaucoma. Ophthalmol Glaucoma. April 21, 2020. [Epub ahead of print].